postcopy: Record largest page size

Record the largest page size in use; we'll need it soon for allocating
temporary buffers.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-7-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

diff --git a/exec.c b/exec.c
index 24cdf642261465370711ac9168670ca3ade91ad4..785d20f648fb9e5b65c236108fb7d53e757798a2 100644 (file)
--- a/exec.c
+++ b/exec.c
@@ -1524,6 +1524,19 @@ size_t qemu_ram_pagesize(RAMBlock *rb)
     return rb->page_size;
 }
 
+/* Returns the largest size of page in use */
+size_t qemu_ram_pagesize_largest(void)
+{
+    RAMBlock *block;
+    size_t largest = 0;
+
+    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+        largest = MAX(largest, qemu_ram_pagesize(block));
+    }
+
+    return largest;
+}
+
 static int memory_try_enable_merging(void *addr, size_t len)
 {
     if (!machine_mem_merge(current_machine)) {

diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 1350c2e441e8eb40493e57c972def457a3addb20..8c305aa4fa02bdc27a8e9c3bb46d95d9ec4ec03d 100644 (file)
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -64,6 +64,7 @@ void qemu_ram_set_idstr(RAMBlock *block, const char *name, DeviceState *dev);
 void qemu_ram_unset_idstr(RAMBlock *block);
 const char *qemu_ram_get_idstr(RAMBlock *rb);
 size_t qemu_ram_pagesize(RAMBlock *block);
+size_t qemu_ram_pagesize_largest(void);
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write);

diff --git a/include/migration/migration.h b/include/migration/migration.h
index 6272adfabad4e1f15cc94873987784f5730137a1..08b98e991158ad94f42af0449eed2b9022b70b94 100644 (file)
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -93,6 +93,7 @@ struct MigrationIncomingState {
      */
     QemuEvent main_thread_load_event;
 
+    size_t         largest_page_size;
     bool           have_fault_thread;
     QemuThread     fault_thread;
     QemuSemaphore  fault_thread_sem;

diff --git a/migration/migration.c b/migration/migration.c
index 481c540a6d5cb605962f2869cc6dc5e45152c907..3dab6845b11f57643db1a20c6ceb75fac1220a55 100644 (file)
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -387,6 +387,7 @@ static void process_incoming_migration_co(void *opaque)
     int ret;
 
     mis->from_src_file = f;
+    mis->largest_page_size = qemu_ram_pagesize_largest();
     postcopy_state_set(POSTCOPY_INCOMING_NONE);
     migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
                       MIGRATION_STATUS_ACTIVE);